Polymer nanocomposites characterization

Keywords Graphene, conjugated polymers, nanocomposites, characterization, properties, optoelectronic application, biological application... 

Adhikari, R. and Michler, G. H. 2009. Polymer nanocomposites characterization by microscopy. 

Inorganic-polymer nanocomposites characterized by exceptional dielectric constant are often called artificial dielectrics . Artificial dielectrics are created when isolated particles become polarized due to the presence of an applied electric field. These novel nanocomposite artificial dielectrics have the potential to posses high dielectric constants (>100) at high frequencies and the low processing temperature associated with polymers. Such a combination of properties is not found in other capacitor materials [180]. Polymer matrices like PMMA, poly(vinylidene fluoride) (PVDF), PS, and polyurethane (PU) have been used. Owing to their physicochemical properties, they represent suitable polymer components for embedding nanoscopic functional inorganic fillers (Table 2). 

Polymer Nanocomposites Characterized by Thermal Analysis Techniques... 

Gilman JW, Bourbigot S, Shields JR et al. (2003) High throughput methods for polymer nanocomposites research extrusion, NMR characterization and flammability property screening. J Mat Sci 38 4451... 

Davis RD, Bur AJ, McBearty M et al. (2004) Dielectric spectroscopy during extrusion processing of polymer nanocomposites a high-throughput processing/characterization method to measure layered silicate content and exfoliation. Polymer 45 6487-6493... 

The dynamic mechanical thermal analyzer (DMTA) is an important tool for studying the structure-property relationships in polymer nanocomposites. DMTA essentially probes the relaxations in polymers, thereby providing a method to understand the mechanical behavior and the molecular structure of these materials under various conditions of stress and temperature. The dynamics of polymer chain relaxation or molecular mobility of polymer main chains and side chains is one of the factors that determine the viscoelastic properties of polymeric macromolecules. The temperature dependence of molecular mobility is characterized by different transitions in which a certain mode of chain motion occurs. A reduction of the tan 8 peak height, a shift of the peak position to higher temperatures, an extra hump or peak in the tan 8 curve above the glass transition temperature (Tg), and a relatively high value of the storage modulus often are reported in support of the dispersion process of the layered silicate. 

Bourbigot, S., Duquesne, S., Fontaine, G., Bellayer, S., Turf, T., and Samyn, F. 2008. Characterization and reaction to fire of polymer nanocomposites with and without conventional flame retardants. Mol. Cryst. Liq. Cryst. 486 325-339. 

The dynamic viscosity and storage modulus of the melt polymer can characterize (1) the degree of dispersity (i.e., intercalation) of the nanocomposite polymer [1,2], (2) the dripping tendency in mesoscale or large-scale fires [3,4], and (3) the structure of the char layer formed during pyrolysis in mesoscale or large-scale fires [5-7]. 

Two specific imaging modes developed in combining ESEM (environmental scanning electron microscopy) and STEM and developed in the MATEIS laboratory can be useful for the characterization of CNT and CNT polymer nanocomposites. 

Haggenmueller R, Zhou W, Fischer JE, Winey KI (2003) Production and characterization of polymer nanocomposites with highly aligned single-walled carbon nanotubes. J Nanosci Nanotechnol 2(1-2) 105-110... 

The first report of TEMT on block copolymer nanostructures, by Spontak [164], appeared in 1988. This was followed by three morphological smdies carried out in the 1990s [165-167]. Only recently has TEMT become more popular in characterizing polymer nanostructures, including block copolymers [134, 164, 167-173], nanocomposites [174, 175], and polymer nanocomposites [176]. Kawase et al. [177] recently presented a protocol to perform complete rotation (i.e., 90°) on a Zr02/polymer nanocomposite, by which they achieved truly quantitative TEMT for the first time. 

Krishnamoorti R, Vaia RA (eds) (2001) Polymer nanocomposites synthesis, characterization, and modeling. In ACS Symposium Series, vol 804. American Chemical Society, Washington... 

Colister, J. 2002. Commercialization of polymer nanocomposites. In Polymer Nanocomposites Sunthesis, Characterization, and Modeling, R. Krishnamoorti and R.A. Vaia, eds.. In ACS Symposium Series No. 804, pp. 11-79, American Chemical Soc, Washington, DC. 

Up to now we considered pol5meric fiiactals behavior in Euclidean spaces only (for the most often realized in practice case fractals structure formation can occur in fractal spaces as well (fractal lattices in case of computer simulation), that influences essentially on polymeric fractals dimension value. This problem represents not only purely theoretical interest, but gives important practical applications. So, in case of polymer composites it has been shown [45] that particles (aggregates of particles) of filler form bulk network, having fractal dimension, changing within the wide enough limits. In its turn, this network defines composite polymer matrix structure, characterized by its fractal dimension polymer material properties. And on the contrary, the absence in particulate-filled polymer nanocomposites of such network results in polymer matrix structure invariability at nanofiller contents variation and its fractal dimension remains constant and equal to this parameter for matrix polymer [46]. 

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